Apparatus for the stabilization of bone fractures

ABSTRACT

The external device for fixing the pins to be inserted into the bone fragments comprises at least one carrier bar, a screw for securing the pins to the carrier bar, a stirrup and a washer for securing the screw to the carrier bar. The stirrup and the washer have at least on the surfaces in contact with the rough surfaces of the bar a deformable lining. The device permits the adjustment of the different parts and improved stabilization of the pins.

DESCRIPTION

The present invention has for its object to provide an apparatus for thestabilization of bone fractures.

It is known at this time that the problem of stabilization withmechanical means of bone fractures, as a substitute for the morecumbersome, obsolete and non functional plaster casting, has beentackled by various surgical teams in the principal countries of theworld.

At the end of 1942 Otto Stader in the United States (U.S. Pat. No.2,393,831) proposed to fix the fracture of long bones by means oftransosseous nails which however had a considerable weight and a lack ofutility in use, in that they did not permit to reduce the fracture inseparate frontal and sagittal planes to put in correct alignment the twodamaged bones to be joined together. This brought about the necessityfor surgical operations dangerous for the patient and with long use ofradiological apparatus for the verification of the two osseous stumps.

In 1945 Roger Anderson in the United States (U.S. Pat. No. 2,477,562)proposed an operating table in association with a device having pinsgoing through for the reduction of the fracture, which howeverconstrained the patient to a long period of immobility, with all theundesirable resulting consequences.

In 1976 a group of researchers of the French Institute ISERM & CERCA(FR-A No. 2,338,692) proposed an apparatus provided with movable clampsalong two parallel guides and with jaws with a spring held by friction.However, the apparatus was cumbersome and complex, requiring complexinvestigations and manipulations to reduce the fracturecontemporaneously in the two vertical and horizontal planes.

In 1978 the american Richard Frederick Kronner (FR-A No. 2,439,002)proposed an apparatus to reduce and immobilise the fracture whichhowever was very heavy, of great encumbrance and difficulty to set up.

In 1979 a group of Czechoslovakian researchers (CH-A No. 738,390)proposed a device to reduce the fracture provided with elements slidableon parallel guides. The locking clamps are very simple and do not permitvariations in inclination and length, as a result of which there islittle possibility of reducing the fracture.

In 1981 Rudolf Kleining (DE-A No. 3,118,397) proposed an over-simplifieddevice in which there was complete lack of a pivot for externaladjustment, as a result of which it was impossible to reduce a fractureafter having placed the apparatus in operation. Because of this, itcould only be used for fractures already reduced, which did not requireinterventions in the apparatus after it was inserted.

Also in 1981 Juan Lazo Zbikowski (FR-A No. 2,517,535) proposed a devicewith screws which were absorbable and aligned, held by clamps ofconsiderable weight and encumbrance, which did not have a very greatstability of retention at a distance, and did not permit to reduce thefracture at the same time in two planes, with great harm for the patientand operators exposed for much time to radiological emissions forverifying the alignment of the skeletal stumps.

In 1981 the present applicants Castaman and Borghettini (IT-A No.85609/81) proposed a device for the stabilization of the fracture oflong bones which offers an easy possibility of reduction in variousplanes, an optimum mechanical stability, a wide versatility resulting atthe same time in a low weight and low encumbrance, with notableadvantages for the patient and for the surgeon.

The present application describes a device which is improved withrespect to the previous invention, both with respect to the manner offixing the bone-traversing pins to the structure of the carrier bar, andwith respect the component parts of the bar itself, in such a manner asto increase the stability of the apparatus during use and thepossibility of adjustment of the parts of the same during the operationof applying it to the limb of the patient.

One of the inconveniences which occur in practice resides in thedifficulty of guaranteeing a secure position at the time of positioningof the various metal pins, which may be threaded, at the time ofinserting them into the individual fragmented bones, for the purpose ofholding them in position, up to the time when they are joined. A secondinconvenience, which occurs sometimes in the use of the abovementionedlocking apparatus (IT-A No. 85609/81) is due to the fact that at thepoint of connection of the parallel portion with the threaded portion,the bar carrying the pin which has passed through the bone is rotated,with grave consequences on the healing of the patient.

All of these inconveniences are eliminated with the adoption of theapparatus improved in accordance with the invention, because the systemfor locking of the bearing elements, which fix the pins passing throughthe bones to the carrier bar of the apparatus is made by means of astirrup and washer both having a deformable lining. Further, theparallel portion of the track of the carrier bar has a rough surfacewhich guarantees an almost immovable fixture of the pins.

The curvilinear connection between the tracked portion and the threadedportion of the carrier bar almost completely eliminates the possibilityof rotation, following the usual manipulations which occur once theapparatus is put to use, guaranteeing the maximum security during use ofthe apparatus.

Other improvements relate to the particular ovoidal shape of thethreaded portion of the carrier bar which permits to orient, intorsional manner, and in the most suitable way, the two parts whichconstitute the carrier bar itself, as required by the particularexigencies of the patient.

A further feature of novelty is constituted by the fact that only one ofthe two carrier bars is fixed to the intermediate pivot by an adjustabletelescopic sysetm, whilst the other forms a unitary body with theintermediate stirrup. This considerably simplifies the manipulation ofadapting the apparatus to the specific case of the patient on which itis applied and also increases the entire stability of the apparatus.

In another embodiment the apparatus is constructed with a series of pinsdisposed on one plane perpendicular to a second series of pins, whichlends itself to the employment of the apparatus in epiphytal fractures,because it permits the placing of a series of pins, traversing theepiphysis, in a plane which is substantially perpendicular to that ofthe series of pins penetrating through the diaphyses.

These and other features of the invention will be better described inthe following and illustrated in the accompanying set of drawings,wherein:

FIG. 1 (sheet 1) represents a front elevational view of an apparatuswith two series of aligned pins;

FIG. 2 represents a profile view of the same;

FIG. 3 is a front view the point of connection between the threadedportion and the guiding tracked portion of the rod carrying the pins;

FIG. 4 is a cross section taken along the line IV--IV of FIG. 3;

FIG. 5 represents a side view, with the parts shown separately, of thelocking screw of a pin.

FIG. 6 (sheet 2) represents, an elevational view of a second form ofconstruction of the apparatus of the invention, intended for epiphytaljoints;

FIG. 7 represents a side view of the same.

FIG. 8 (sheet 3) represents schematically a bone joint with indicationof the points of insertion of the pins in the apparatus for epiphytaljoints according to FIGS. 6 and 7;

FIG. 9 represents a side view of the same;

FIG. 10 represents schematically and in side view a bony structure withindication of the points of passage of the pins, in the case ofintermediate bone fracture.

The apparatus illustrated in FIGS. 1 to 4 is particularly adapted to beemployed in central fractures of long bones.

This comprises a pivot block 1 which is connected, by means of the screw2 to the bracket 3, with which is integral the tracked bar 4 carryingthe pins 5.

On the side opposite to the block 1 there is fixed the threaded socket6, on which in its turn there is screwed the threaded stud 7, integralwith the second tracked bar 8 carrying the pins 9.

It will be seen that the screw 7 (FIGS 3 and 4) has an ovoidal sectionin which the threads are limited to the two opposed sections 10 and 10',while on one of the two curved surfaces, but not threaded, there restthe headless threaded screw 10" and 10"' having a shaping of the headwhich does not permit locking.

Two screws with mutually convergent axes guarantee alone an optimumlocking, and the two opposite screws can be omitted when not needed.

Analogously the screw 11 guarantees an optimum pressure on the flatcentral non threaded portion of the socket 6, which in this mannerremains rigidly fixed to the pivot block 1.

On the flat roughened surfaces of the carrier bars 4 and 8 there arefixed, as has been mentioned, the respective pins 5 and 9, by means ofthe screw 12 fixed to the respective bar by means of the nuts 13, bymeans of the stirrup 14 and the washer 15, both provided with a layer ofdeformable material, respectively 14' and 15', which comes to bear onthe roughened surfaces 4 and 8 of the slotted portions of the carrierbars.

The normal metallic washer 16 bears directly on the underside of the nut13, assuring a firm locking of the latter on the stirrup 14.

In FIGS. 6 and 7 it will be seen that the series of pins 17 is disposedin a plane which is perpendicular with respect to the series of pins 18,because this second form of construction of the apparatus is intendedfor the stabilization of epiphytal osseous fractures.

In this case, the carrier bar of tracked construction is single and isshown with the reference numeral 19. This bar is intended to carry thepins 18 for insertion into the osseous diaphyses, while the pins 17intended for insertion into osseous epiphyses are simply fixed to thedrilled shank 20, provided with a nut 21 and washer 22, which locks thepin 17 to the socket 23 of the threaded portion 24 of the carrier bar,in its turn fixed by the socket 25 and pivot 26, to the tracked portion19 of the carrier bar.

In the first case there are provided simple channels, with parts ofcircular section, formed on the block 27, on the washer 28 and on theblock 29 disposed facing the pins 17. The pins 18 are, on the contrary,fixed to the tracked portion 19 of the carrier bar, by means of boltswith nuts, washers and stirrups, provided with a deformable coating,analogously to what has been described in the first form of constructionof the apparatus illustrated in FIGS. 1 to 5.

Also in this case however, while the pins 17 are connected to thepivoting element 26, by means of the socket 25 of adjustable position,so as to permit a lengthening of the distance between epiphysis anddiaphysis, the tracked portion 19 is connected to the stirrup 30, whichis in its turn fixed by means of the nut 31 to the pivot 26, through theneck 32, of curvilinear shape, the shaping of which is such as toeliminate the possibility of rotation which would be extremely dangerousfor the recovery of the patient.

In FIGS. 9 and 10 there are shown the points of insertion of the pins17, into the epiphysis 33, whilst the pins 18 penetrate into thediaphysis 34 of the bone, the line of fracture of which is shownschematically by the line 35.

In the case of fracture of a central portion of a long bone, the pins 5and 9 (FIG. 10) are inserted at opposite parts with respect to the lineof intermediate fracture 36.

It is to be noted that the apparatus now described could be usefullyemployed also for artificial lengthening of the joints, by means ofperiodical adjustment of the position of the respective threaded sockets6 and 25, which brings about the resultant increase of the distancebetween the truncated bones and successive regrowths of the same, inaccordance with the by now well known treatments in the field.

Naturally this will be facilitated by the presence of means ofadjustment 10", 10"' and 11 (FIG. 1) which, when loosened, permit thelengthening of the apparatus by simple rotation of rotating means or byrotation in its turn of the socket 6 and successive stabilization for asuccessive period of regrowth of the osseous callus.

Naturally, the constructive features of details of the apparatus, suchas for example the number of pins or the position thereof, thedimensions of the various parts and the particular finish, can assumevarious shapes and aspects with respect to those now described andillustrated on the set of accompanying drawings, provided that theessential features, set out in the successive claims, remain the same,without thereby exceeding the scope of the invention.

What is claimed is:
 1. An external device for use in orthopedic surgeryfor fixing pins adapted to be secured to bone fragments, comprising apivot block (1, 26), at least one carrier bar (4, 8, 19) fixed to saidpivot block, bone-traversing pins adapted for insertion into bonefragments, at least one first element (12) for securing the pins to saidcarrier bar, said carrier bar having in part a rough surface, means forlocking said first element (12) to said carrier bar, said meansconsisting of a stirrup (14) and a washer (15) located on either side ofsaid carrier bar, said stirrup and said washer having at least thesurface in contact with said rough surface of said bar covered with adeformable lining, a second element (13) for clamping said stirrup andsaid washer to said first element (12).
 2. The device according to claim1 wherein said first element (12) is a screw and said second element isa nut.
 3. The device according to claim 1 which comprises two carrierbars, each carrier bar comprises a tracked structure, one trackedstructure has a stud (7) connecting said tracked structure to said firstelement and a section of said connecting portion has reduced crosssectional area, wherein said stud (7) has threaded portions (10, 10¹)having opposed flat portions, said pivot block is fixed to a socket (6),said socket has a threaded portion, the threads of said stud (10, 10¹)being operatively engageable with the threads of said socket.
 4. Thedevice according to claim 3 wherein said socket has an external portionadapted to be connected to said pivot block.
 5. The device according toclaim 1 which comprises one carrier bar (19), said carrier bar (19)carries an alternate first element (20) for securing a plurality of pins(17) generally perpendicular to the longitudinal axis of said carrierbar.
 6. The device according to claim 5 wherein the pivot block (26) hasa socket (25) fixed thereto, said carrier bar has a threaded portion(24) and has an eye (23) to receive said alternate first element, saidthreaded portion (24) being fixed to said eye (25).